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[darren.naish@port.ac.uk: 52nd SVPCA meeting]
Dear DMLers,
I'm forwarding this summary of SVPCA 2004 on behalf of ex-HP Darren
Naish. I notice, skimming through this report (I've not read it
properly myself yet) that Darren gives an extremely sketchy report of
his own talk: "Darren Naish discussed _Yaverlandia_." For those who'd
like to know more, you can read the abstract of his talk on the SVPCA
web-site at
http://www.svpca.org/2004/abstracts/svpca-papers_a.htm#abst11
I leave it to him whether he wants to reveal the punchline in this
forum, or wait for it to be published.
One other note: my memory of Kristian Remes's talk differs from
Darren's in that I believe he recovered "Barosaurus" africanus as
closer to _Barosaurus_ than to other genera (but still a distinct
genus, for which he uses the name _Torneria_).
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From: "Darren Naish" <darren.naish@port.ac.uk>
Organization: University of Portsmouth
To: mike@indexdata.com
Date: Thu, 16 Sep 2004 12:19:04 +0100
Subject: 52nd SVPCA meeting
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Hey Mike - will reply to your emails later today. Please fwd
this to the DML....
- ---------------------------------
The 52nd SVPCA was held at the University of Leicester
from the 8th to the 10th of September 2004 (the field trip was
on the 11th but I didnÂt go in an effort to keep costs down).
The meeting ran really smoothly and many people have said
how much they enjoyed it, though at least some speakers
would have done well to do their homework on the AV
facilities _before_ standing up and doing their talk. The
meeting was also really well attended, with a higher turn-
out than some recent ones, and I also felt that the timetable
was well balanced, with a good and fair representation of
fish, Palaeozoic tetrapods, Mesozoic reptiles and mammals.
Mammal talks were on marsupial functional morphology
and ontogeny, lipotyphlan relationships, basal artiodactyls,
Pleistocene hyaenas, and both Eocene and extant primates.
Apologies to the workers involved and those interested, but
(in keeping with my tradition of sticking to both
palaeoherpetology and Mesozoic-oriented things) I have
resisted the temptation to write reviews of those
presentations too. I have also not reported on the posters:
these included new details on _Hylaeosaurus_ (Gray and
Chapman), humeral morphology of _Saturnalia_ (Gabriel
and Langer), details of confuciusornithid morphology
(Hughes), _Tyrannosaurus_ biomechanics (Hutchinson et
al.), rhynchocephalian skull evolution (Jones),
_Peloneustes_ (Ketchum), Miocene leatherback turtles
(Lindow), a hyperossified Madagascan Cretaceous
megafrog (Smith et al.), and others.
The group photo (or, as one speaker termed it, the Âstaring
into the sun for five minutesÂ) was taken on the Thursday,
and as some of you will know this is the day that _Nature_
published the parental care in psittacosaurs paper. This
explains why IÂm holding up a page from a newspaper in
the photo. Perhaps the highlight of the meeting was seeing
Darwin himself depicted as Neo (with shades and long
leather coat) in the title slide of Stig WalshÂs ÂDarwin
versus The Matrix: does artificial intelligence have a place
in vertebrate palaeontologyÂ?
The abstracts of the meeting have been published asÂ
Evans, M. & Forrest, R. 2004. _52nd Symposium of
Vertebrate Palaeontology and Comparative Anatomy, 8th-
11th September 2004 and 13th Symposium of
Palaeontological Preparation and Conservation, 7th
September 2004, Abstracts_. University of Leicester.
My congratulations to the organisers (Mark Evans, Richard
Forrest and Mark Purnell) on arranging such a fun and well
organised meeting.
- -- Stem-group tetrapods
Jamie Robinson showed some fantastic animated 3D
computer reconstructions of the basal temnospondyl
_Dendrerpeton_. The specimen (BMNH R436) has both
stapes preserved, with the left lodged inside the cranial
cavity and thus invisible to human eyes. It seems that
_Dendrerpeton_ had an impedence-matching middle ear
homologous with that of anurans.
Jennifer Clack spoke about a new, fifth tetrapod taxon from
Devonian East Greenland, collected in 1947 from Celsius
Bjerg (the new taxon has a name, and this was used in the
presentation). It includes good skull material, showing that
it had a smoother skull texture than _Acanthostega_ and
other taxa, and it also differs from other named taxa in
lateral line morphology and dentition.
Per Ahlberg reviewed our current understanding of the large
stem-group Devonian tetrapod from Latvia, _Ventastega
curonica_. _Ventastega_ is known from many many
specimens representing most of the skeleton, this making it
the most complete stem-group form after _Ichthyostega_
and _Acanthostega_. In details, _Ventastega_ more recalls
_Acanthostega_ than other taxa, but appears to be even
more basal than this genus. Like _Acanthostega_,
_Ventastega_ has a bizarre internasal fontanelle (a median
opening along the dorsal midline of the snout), the function
of which remains unknown.
- -- Lepidosaurs
Susan Evans talked about the Lower Cretaceous lepidosaurs
of Pietraroia, Italy. _Chometokadmon_, originally described
as a lizard but later reinterpreted as a rhynchocephalian, is a
lizard after all and clearly a scleroglossan, an anguimorph
and perhaps a stem varanoid close to _Parviraptor_.
Scattered osteoderms preserved in the region of the orbit
and temporal region show that they were arranged in this
area in a manner perhaps similar to that of extant
_Lanthanotus_. Ardeosaurids (including a new species of
_Eichstaettisaurus_ named after Steve Gould) and among
the last Laurasian rhynchocephalians indicate that Pietraroia
had a relictual lepidosaur fauna, probably because  like the
rest of Europe at this time  it was a region of archipelagos
and isolated islands.
Nick Arnold showed how different anatomical characters
have different degrees of lability, and by considering this
area more carefully we might be able to use these degrees of
lability to better assess their value in phylogeny. For
example, body size and the gracility and flexibility of toes
in lizards are highly labile between closely-related taxa. At
the other extreme, lizards which have fused their eyelids
together end up lacking all of the structures associated with
the maintenance of Ânormal eyes (e.g., they lack lacrimal
glands and eyeball musculature), and they then seem totally
unable to reverse this character. The implication from this
for phylogenetic analysis is that characters which appear not
to be labile, or in fact to be irreversible, should be weighted,
though note that this is my interpretation and IÂm not sure if
Nick actually stated this (sorry!).
Jason Head discussed an analysis of snake diversity in the
Eocene sediments of the Hampshire Basin, an area
preserving one of the best snake fossil records in the world.
Application of PCA and statistical analyses to snake
vertebrae (Jason was focusing in particular on erycines)
show that previous taxonomic assignments are inaccurate
and that the number of species within faunas are probably
over-estimated.
- -- Plesiosaurs
Leslie Noe discussed the role of the plesiosaur neck,
combining evidence from functional morphology, tooth
wear, stomach contents, palaeoecology and
palaeoenvironment. The morphological evidence from the
plesiosaur neck indicates that dorsal and lateral movement
of the neck was restricted, but that extensive ventral
movement was possible. Long-necked plesiosaurs mostly
seem to have lived in places where there was a diverse
fauna of bottom-dwelling invertebrates, so the notion of
plesiosaurs as grazers of the benthic fauna was advocated.
Like grazing bovids, plesiosaurs may have spent a lot of
time with the neck and head bent downward. Danger
threatens (i.e., a pliosaur), and the plesiosaur relaxes the
system, bringing the neck back into line with the rest of the
vertebral column, and now it can escape at speed.
In ÂReinforced hoses and rhomaleosaursÂ, Richard Forrest
pondered the internal structure of industrial and domestic
hoses. Some hoses have circular reinforcement, with wire
hoops perpendicular to the long axis. Richard couldnÂt find
a tetrapod with this morphology and resorted to the neck of
toy Imperial walkers, this being the second presentation I
know of that has used Imperial ground-assault transport to
illustrate a point (ask Matt Bonnan). In other hoses,
reinforcement runs at 45 degrees to the long axis. In
rhomaleosaurs, possible bracing structures in the cervical
vertebrae (in the zygapophyses and rims of the
synapophyses) are also aligned at 45 degrees, as apparently
are the lines of reinforcement in the skull. This bracing
system seems to be part of a functional complex in
rhomaleosaurs, associated with their conservative cervical
count (28 verts or thereabouts). Rhomaleosaur diversity
seems to be higher than presently reflected in the literature,
with various new, unnamed taxa sitting in various
collections. Lower Jurassic plesiosaur diversity is probably
far higher than currently recognised in fact (see also
GrossmanÂs data, below).
Norton Hiller reviewed elasmosaurid diversity in the Late
Cretaceous of New Zealand  besides _Mauisaurus haasti_
and _Tuarangisaurus keyesi_ there are two other, new taxa.
One of these is represented by a good pectoral girdle. This
preserves an unusual craniocaudally elongate sulcus on the
medial surface of the coracoids and a massive prominent
spike-like process on the ventral surface. The latter feature
is not entirely novel as itÂs also seen in a new elasmosaurid
being described by Pat Druckenmiller. Norton wasnÂt aware
of any possible function for this spike but in discussions
with Colin McHenry IÂve learnt that it is probably related to
the presence of a sternum. Supposed records of
_Tuarangisaurus_ and _Mauisaurus_ from Antarctica and
southern South America are dubious and probably mostly
not referable to these taxa.
Franziska Grossmann gave a talk on the good Lower
Jurassic plesiosaur record from the German Posidonia shale
and new reconstructions were presented on the hitherto
neglected taxa _Plesiosaurus guilelmiimperatoris_ and _P.
brachypterygius_, both are which are quite different in
many details from _P. dolichodeirus_ (the type of the
genus). IIRC, _P. guilelmiimperatoris_ had a particularly
odd, box-like skull shape. _P. brachypterygius_ has a more
conventional plesiosaur skull. Inclusion of these taxa within
a novel phylogenetic analysis showed that, as expected,
they are well aware from _P. dolichodeirus_.
- -- Pterosaurs
David Unwin combined various lines of evidence to paint a
well integrated and supported view of pterosaur
reproductive biology. ItÂs the first conference presentation
IÂve ever seen that was illustrated with Jenny Halstead
illustrations, but then you canÂt have everything (sorry, I am
not a fan). Pterosaurs were clearly oviparous and new
specimens confirming this are in press. The eggshell of the
new embryo does not appear to be calcareous as argued but
indicates instead that pterosaur eggshells were leathery. The
recently described Chinese embryo plots with adult
ornithocheiroids in terms of limb proportions, and all
indications are that baby pterosaurs were precocial and able
to fly soon after hatching. Preserved soft tissues show that
hatchling pterosaurs had wing membranes as extensive of
those of adults and pterosaur growth rates were slow
compared to those of birds and bats.
- -- Mesozoic faunas etc.
Steve Sweetman spoke about his many new discoveries
from the Isle of WightÂs Wessex Formation. There were
pretty much no published Wessex Formation
microvertebrates prior to SteveÂs work  now there are
loads: multiple new taxa of lissamphibians
(albanerpetontids, salamanders and frogs), lizards, and
mammals (including MTBs, spalacotherioids, and basal
zatherians). There are also various strange little dinosaur
teeth, some of which are problematical (e.g., those that
resemble basal ornithischian teeth), others of which are new
records (e.g., troodontids).
Jean-Paul Billon-Bruyat reviewed the Kimmeridgian fauna
of NW Switzerland, as revealed by body fossils and
trackways. The environment represents a shallow carbonate
platform, and chelonian and crocodyliform elements are
present. A fragment of pterosaur has been discovered, but it
is literally only a fragment. Numerous sauropod and
theropod trackways are present which, in the case of the
sauropods, raised the question as to what the animals were
doing there. They actually appear to have been making a
living in the area and not simply passing through (as has
been argued for other marginal environments with
herbivorous dinosaur taxa).
Mike Benton discussed Âecosystem remodelling across the
P-Tr boundary as documented in the record of the South
Urals basin. A fundamental change and simplification in
guild structure occurred across the boundary  small
piscivores and insectivores, mediun and large carnivores
and large herbivores were all lost, and these guilds remained
empty for 25 million years after the extinction event.
- -- Chelonians
Sarah EarlandÂs talk title ÂTurtle taphonomy and tuna fish
sandwiches was explained as a clever ploy to attract
attention to a talk whose content did not necessarily match
that of the title. Basically: what happens to dead turtles that
rot in water? Very little has been published on turtle
taphonomy, so actualistic work is needed. Think crabs,
maggots, bacterial films, dangling limbsÂ
- -- Crurotarsans
Rebecca Smith analysed various characters in the
steneosaur skull to see if the various species reported from
the Upper Lias of the Yorkshire coast were valid and could
be distinguished, a study initiated by the rediscovery of a
skull referred to _Steneosaurus brevior_. The measurements
taken (e.g., orbit width) were compared to sets of
measurements of the same features taken from a wide
sample of extant crocodylian species to see how labile these
features were.
- -- Dinosaur biology, diversity etc.
Phil Manning addressed various aspects of
palaeoichnology. Phil argued that underprints, ghost prints,
transmitted prints or whatever you want to call them are far
more common than has been hitherto recognised  in fact, a
quick analysis of the published track record suggested that
something like 80% of all published dinosaur tracks were
not the actual surface tracks themselves, but underprints!
Accordingly, the distortion of sediments must be an
important factor in print anatomy. Indeed, the deeper the
same print is transmitted through the sediment, the more
different it becomes, such that the interdigital angles of a
deep impression is >totally< different from a shallow
impression of the same track. This all casts significant doubt
on proposals that dinosaur groups with similar foot anatomy
can be reliably distinguished from tracks, and it also
indicates that track ichnospecies are massively oversplit.
Mike P. Taylor summarised his study of non-avian dinosaur
diversity, looking at diversity within clades, geographic
regions and year based on all valid genera recognised as of
2001. Some ornithischian groups (pachycephalosaurs and
stegosaurs) are taxonomically insignificant and theropods
proved ridiculously abundant proportionally. The
Kimmeridgian and Campanian were the most dinosaur-rich
stages. The naming of taxa over history is interesting, with a
plateau between the wars and a massive rise within the past
19 years: more taxa have been named in this time than
during the preceding 158 years.
John Hutchinson posed the fundamental question can we
incorporate enough information into biomechanical
modelling to ever get even close to real-organism
modelling, or are we just **cked? (his words, not mine).
Things need to move on a long way from the important
studies of Alexander, and one of the take-home points was
that we need far more people working on extant animals,
many many aspects of which are still not understood or
even not studied at all. The use of elephants and rhinos as
analogues for dinosaur locomotion for example (as per
Alexander, Bakker and others), is problematic as the
biomechanics of these species are horribly understudied.
Oliver Wings covered the results of his project on gastrolith
distribution and function. Some lovely photos of dissected
ostrich stomachs. While gastroliths have been reported
widely among birds, their reported presence among birds of
prey (falconiforms and strigiforms) appears due to ingestion
of other animals which were instead the proper Âowners of
the gastroliths. Many non-avian dinosaurs for which
gastroliths have been reported (including all theropods
except _Caudipteryx_ and _Sinornithomimus_ and all
thyreophorans) have only ever been discovered with one,
two or a few gastroliths. This suggests accidental ingestion,
not deliberate employment. OliverÂs most controversial
assertion was that sauropods could not have used gastroliths
for digestion because they never preserve a mass of stones
big enough to have made a digestive difference. Paul
Upchurch thought that this was problematic because it
assumed that sauropods had a digestive apparatus and
metabolism just like that of birds.
- -- Sauropodomorphs
Tim Fedak gave a presentation on his work on the Nova
Scotian sauropodomorphs of the McCoy Brook Formation.
New specimens include adults, subadults and juveniles and
details of the ilia and other elements show that these are not
_Ammosaurus_ as previously thought, but a new taxon. Tim
has been working on the histology of this taxon and also
considered various aspects of ontogeny, growth rates and
histological variability. There appears to be a new taxon of
theropod in the McCoy Brook Formation.
Andreas Christian applied analysis of compressive forces to
sauropod necks  those of you familiar with this research
will known thatÂs been applied to _Brachiosaurus_, the
conclusion from Christian et al. being that _Brachiosaurus_
had a vertical mast-like neck. Christian explained the
technique, showed that it worked when applied to such
living animals as giraffes and camels, and then applied it to
other sauropods. The data from _Diplodocus_ indicates a
horizontal neck but that from _Euhelopus_ indicates that it,
too, had a mast-like vertical neck.
Kristian Remes presented a reanalysis of the type material
of the Tendaguru sauropod _ÂBarosaurus africanus_. While
this valid taxon does indeed seem to be a diplodocid
diplodocoid, it is not closer to _Barosaurus lentus_ than to
other taxa, and indeed is significantly different from it in
many features. Kristian therefore argued that the older name
_Tornieria africana_ should be resurrected for this taxon.
Rebbachisaurid distribution indicates that diplodocoids
were ancestrally Gondwanan (though _Histriasaurus_ was
not mentioned): Paul Upchurch countered this by arguing
that the groupÂs distribution was more likely ancestrally
global, with their post-Callovian distribution being due to
vicariance.
Also on diplodocoids, Daniela Schwarz covered her new
work on reconstructing the cervical column pneumaticity of
_Diplodocus_. Daniela showed many fantastic photos and
complex reconstructions, covering both juveniles and adults
and with an attempt to reconstruct the ontogenetic changes
that occurred. The models of air sac distribution were
extremely detailed and highly complex, and pneumaticity
became more complex during ontogeny. As well as air sacs
lateral to the centrum, dorsal to the neural arch and
elsewhere, there is evidence for several sacs within the
neural canal.
- -- Theropods
Steve Hutt presented data on a recently discovered
spinosauroid dorsal vertebra from the Barremian Wessex
Formation of the Isle of Wight. After eliminating
_Neovenator_ and _Becklespinax_, Steve showed that the
specimen was highly similar to the dorsal vertebrae of the
_Baryonyx_ holotype, albeit it with a far taller neural spine.
The spine is in fact comparable to that of _Suchomimus_.
However, careful examination of the _B. walkeri_ spines
show that they are not complete but in fact only one-third
so, and the holotype probably originally had neural spines
comparable to those of the new Isle of Wight specimen.
Steve agreed with other authors that _Suchomimus_ is
probably not a distinct genus but a species of _Baryonyx_.
In a second talk on spinosauroid material, Eric Buffetaut
revealed new good theropod postcrania from the Lower
Cretaceous Sao Khua Formation of Thailand. This material
is associated with teeth referable to _Siamosaurus
suteethorni_ and is thus probably also referable to this
species, though this canÂt be established without question
because the teeth could be there because of scavenging. The
cervical and dorsal vertebrae of the new specimen are
highly similar to those of _Baryonyx_ in many details,
similar enough to establish the spinosaurid spinosauroid
nature of the new specimen with confidence. The tall neural
spines on the dorsal vertebrae were comparable with that of
the _Baryonyx_ vertebra described by Hutt in the previous
presentation.
Darren Naish discussed _Yaverlandia_.
Gareth Dyke reported new bird material from the Upper
Cretaceous Northumberland Formation of Hornby Island,
British Columbia. Like the rest of NW North America, this
area is part of an accreted microterrane and was not a part of
the North American continent during the Cretaceous, thus
its taxa may well be closer to animals from elsewhere
(notably eastern Asia). The birds represented are known
from isolated bones of apparently marine taxa and include a
euenantiornithine and an ornithurine that may be an
ichthyornithiform. The euenantiornithine was compared to
_Halimornis_.
David Waterhouse showed his new psittaciform phylogeny.
With the exception of one problematic taxon, pseudasturids
were stem-group psittaciforms (as argued recently by
Gerald Mayr) and several psittacid groups proposed by
other workers to be clades were also supported as
monophyletic, including cockatiels and cockatoos, lorikeets,
and South American taxa. _Coracopsis_ (vasa parrots) were
close to the psittacid root, which again is interesting
because other people have suggested this based on other
bits of evidence. Several characters which exhibit
interesting (and presumably phylogenetically significant)
diversity remain to be coded across all taxa, and this will be
the subject of future work. These characters include bill
shape, feather pattern and the presence of feather patches
that fluoresce under UV light.
- -- Synapsids
Arthur Cruickshank discussed the _Dicynodon_ species of
the Upper Permian of Morayshire, Scotland. A natural
mould of a virtually complete skull was examined by way
of CT-scanning, MRI and other techniques and various
details showed it could be referred to _D. traquairi_, and
Arthur asserted that this species can be distinguished from
_D. lacerticeps_. Some of these species have a notch in the
dentary symphysis which suggests that they might have had
a prehensile tongue, though IÂd be interested if thereÂs any
evidence from the hyoids or elsewhere in agreement with
this (dicynodont hyoids were pretty gracile so far as I
know).
Tom Kemp advocated a fairly controversial point of view
that many of us who work on morphology might not like
hearing. Attempts to reconstruct the total phylogeny of
placentals were never particularly convincing, nor did they
produce well resolved trees, nor were any nodes supported
by multiple characters. It is the many independent molecular
studies that seem to have sorted things out. Kemp therefore
argued that morphology alone can probably never get it
right, and if we look at phylogenies for fossil taxa we see
that some trees, and some nodes in trees, are incredibly
weak, and maybe we should have next to no confidence in
these phylogenies (non-mammalian therapsids were used as
the case study). Robert Asher pointed out after this talk that
maybe this point of view was somewhat negative: after all,
morphological work had been able to recover at least some
chunks of the clades recognised by molecular work (e.g.,
morphology-based Archonta constitutes a chunk of
molecular Euarchontoglires and morphology-based
Paenungulata constitutes a chunk of molecular Afrotheria).
Robert Presley showed quite convincingly that the groove
on the medial surface of the Mesozoic mammal mandible
should not be called Meckelian sulcus or anything like this
and for various reasons we should return to calling this
structure Âinternal mandibular grooveÂ.
Ian Corfe reviewed the taxonomy of _Oligokyphus_ and
showed that various tooth-cusp characters used to
distinguish putative species were erroneous and some
named species, when examined using quantitative
morphometrics, plotted together.
- --
Darren Naish
School of Earth & Environmental Sciences
University of Portsmouth UK, PO1 3QL
http://web.port.ac.uk/departments/sees/staff/NaishD.htm
email: darren.naish@port.ac.uk
tel: 023 92846045
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